不同关节角度肌肉等长最大自主收缩抗阻力训练的神经适应分析

Neural Adaptation Analysis of Muscle Isometric Maximum Voluntary Contraction Resistance Training at Different Joint Angles

目的研究不同关节角度下肌肉等长最大自主收缩(maximum voluntary contraction,MVC)抗阻力训练神经适应特点。方法将30名健康男性大学生随机分成3组,每组分别做肘关节角度在45°、90°、135°MVC等长收缩抗阻力训练,测量训练前后肱二头肌的表面肌电(surface electromyography,s EMG)信号,并分析s EMG信号的均方根(root mean square,RMS)和中位频率(median frequency,MF)。结果肘关节45°、90°、135°训练前后肱二头肌s EMG的RMS标准化值存在显著性差异。训练后不同角度之间RMS相比,45°与90°、135°均存在显著性差异,而90°与135°之间则不存在显著性差异。训练后各角度MF标准化值均不存在显著性差异。结论 s EMG的RMS呈现角度特异性变化,而s EMG的MF不具有角度特异性。当肱二头肌处于中、大肘关节角度时,等长抗阻力训练产生的神经适应效果较好。

Objective To study the characteristics of neural adaptation for resistance training of maximum voluntary contraction( MVC) of muscles at different joint angles. Methods Thirty healthy male college students were randomly divided into 3 groups,and each group was subjected to MVC isometric contraction resistance training at elbow joint angles of 45°,90°,and 135°. Surface electromyography( sEMG) signals of the biceps brachii were measured before and after training,and the root mean square( RMS) and median frequency( MF)of the s EMG signals were also analyzed. Results There were significant differences in normalized RMS of sEMG for the biceps brachii before and after training at 45°,90°,and 135° elbow joints. Comparison of the RMS between different angles after training showed that 45° was significantly different from 90° and 135°. There were no significant differences between 90° and 135°. After training,no significant differences were found in normalized MF at all angles. Conclusions The RMS of sEMG shows angle-specific changes,while the MF of s EMG does not have angle-specific changes. When the biceps brachii is at the middle and large elbow joint angles,the neural adaptation effect produced by isometric resistance training is better.